1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly to a semiconductor device having an on-chip reference timing generator and that is capable of testing the chip's operation with high accuracy in accordance with the reference timing.
2. Description of the Related Art
In recent years, the operating speed of semiconductor devices has been improved along with their increasing miniaturization and the increasing reduction of the power consumption. For example, the operating frequency of a high-speed memory has become higher than 200 MHz, and the access time has been shortened to about 2.5 ns. In order to ensure the quality of semiconductor devices operating at such a high speed, it is necessary to test the semiconductor chips using high accuracy large scale integrated circuit (LSI) testers before shipment.
In the semiconductor devices of the related art, high-speed operational clock signals were supplied to the chips for testing. Expensive LSI testers were necessary for checking the operation. Further, since the measurement accuracy of LSI testers was limited, the test precision deteriorated when the measurement error of the LSI testers was greater than the required specifications. As a result, there was the disadvantage that errors were liable to occur in judging the quality of semiconductor chips.